PHP 8.1 – Deprecate autovivification on false

You won’t be able to initialize array from falsy values any more this include: only false values and nothing else.

PHP 8.1 will continue to allow autovivification from undefined variable and null, but in every other case an error message will be shown:

Cannot use a scalar value as an array

Allowing autovivification on null can be a sign of a buggy code, but it is less of a problem than false. In PHP, null and undefined are very similar and often treated the same way, e.g. isset() and ??.

Appending array keys to a variable of type false will display a deprecation notice like:

Deprecated: Automatic conversion of false to array is deprecated in XXX

In PHP 9.0, this will throw a fatal error, the same as for other scalar types.

More about PHP 8.1

Read about all PHP 8.1 features and changes in here.